Datasheet

ADP2503/ADP2504 Data Sheet
Rev. C | Page 12 of 16
UNDERVOLTAGE LOCKOUT
The undervoltage lockout circuit prevents the device from oper-
ating incorrectly at low input voltages. It prevents the converter
from turning on the power switches under undefined conditions
and, therefore, prevents deep discharge of the battery supply.
V
IN
must be greater than 2.25 V to enable the converter. During
operation, if V
IN
drops below 2.10 V, the ADP2503/ADP2504
are disabled until the supply exceeds the UVLO rising threshold.
THERMAL SHUTDOWN
When the junction temperature, T
J
, exceeds 150°C typical,
the device goes into thermal shutdown. In this mode, the power
switches are turned off. The device resumes operation when the
junction temperature again falls below 125°C typical.
SHORT-CIRCUIT PROTECTION
When the nominal inductor peak current value of 1.5 A is
reached, the ADP2503/ADP2504 first switch off the NMOS2
transistor if it is active. If the current thereafter continues to
increase by an extra amount of 200 mA, the PMOS1 transistor
is also switched off. This operation is reversible when the short
circuit stops. It allows the inductor current ripple to be mini-
mized close to 1.5 A and, thus, the controller to restore V
OUT
even if a high load current is maintained after the short circuit.
REVERSE CURRENT LIMIT
In case of a short circuit on V
OUT
to a value greater than
expected, the inductor current becomes negative (reverse
current). The negative peak value is limited to 1.1 A by
deactivating the PMOS2 switch.